CA1100069A - Method of removing ash components from high-ash content coals - Google Patents
Method of removing ash components from high-ash content coalsInfo
- Publication number
- CA1100069A CA1100069A CA274,208A CA274208A CA1100069A CA 1100069 A CA1100069 A CA 1100069A CA 274208 A CA274208 A CA 274208A CA 1100069 A CA1100069 A CA 1100069A
- Authority
- CA
- Canada
- Prior art keywords
- coals
- solution
- ash components
- coal
- carbonate solution
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/005—General arrangement of separating plant, e.g. flow sheets specially adapted for coal
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
- C10L9/00—Treating solid fuels to improve their combustion
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S75/00—Specialized metallurgical processes, compositions for use therein, consolidated metal powder compositions, and loose metal particulate mixtures
- Y10S75/958—Specialized metallurgical processes, compositions for use therein, consolidated metal powder compositions, and loose metal particulate mixtures with concurrent production of iron and other desired nonmetallic product, e.g. energy, fertilizer
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Processing Of Solid Wastes (AREA)
- Solid Fuels And Fuel-Associated Substances (AREA)
- Carbon And Carbon Compounds (AREA)
Abstract
ABSTRACT
A method of removing ash components from coals, particularly high-ash content coals, comprises grinding the coal into ground particles and suspending the ground coals in an aqueous alkali carbonate solution. The solution is maintained in a reactor for 45 to 120 minutes at a temperature range of from 250°C to 280°C and under a pressure of from 50 to 80 atm in order to cause the CO2 is discharged from the reactor and discharging the CO2 with the gas stream.
The suspension is stirred and agitated at elevated tempera-tures and increased pressures in order to fuse the ashes.
The aqueous solution containing the dissolved ash components is then separated from the coal. The removed carbon di-oxide is introduced into a solution for reforming the alkali carbonate in order to cause the contents of the solution to become insoluble and separated and the alkali solution to become regenerated. The regenerated solution is then used to continue the operation by forming a further aqueous alkali carbonate solution and ground coal suspen-sion.
A method of removing ash components from coals, particularly high-ash content coals, comprises grinding the coal into ground particles and suspending the ground coals in an aqueous alkali carbonate solution. The solution is maintained in a reactor for 45 to 120 minutes at a temperature range of from 250°C to 280°C and under a pressure of from 50 to 80 atm in order to cause the CO2 is discharged from the reactor and discharging the CO2 with the gas stream.
The suspension is stirred and agitated at elevated tempera-tures and increased pressures in order to fuse the ashes.
The aqueous solution containing the dissolved ash components is then separated from the coal. The removed carbon di-oxide is introduced into a solution for reforming the alkali carbonate in order to cause the contents of the solution to become insoluble and separated and the alkali solution to become regenerated. The regenerated solution is then used to continue the operation by forming a further aqueous alkali carbonate solution and ground coal suspen-sion.
Description
llO~Q69 This invention relates in general to methods of removing ash from coals and, in particular, to a new and useful method of removing ash components from high-ash content coal in which the ground coal is suspended in an aqueous alkali carbonate solution.
The present invention relates to a method of removing ash components from coals, paxticularly high-ash bituminous and sub-bituminous coals, in which the coals are ground, suspended in aqueous, alkaline-reacting, solutions and the ashes are fused at an elevated temperature and increas-ed pressure under stirring motion and, thereupon, the coals are separated from the a~ueous extract.
A method is known from "BIOS FINAL REPORT 522, item 30", in which the ine coal, freed in advance from a part of its ashes in a ~lotation process, is mixed w~th 5.6 times the amoun~ of a 2.5 percent sodium hydrox-ide ~olution, the suspension i8 kept for 20 minutes under 100 to 200 atm at 250C, the liquor is then separated and the coal is washed with water and hydrochloric acid.
For this purpose, 140 kg of cau~tic soda are needed per metric ton o coal.
~rom U.S. Pa~ent No. 2,556,496, there is further known an ash xemoval process in which the coal is ex-tracted at temperatures bet~en 120C and 130C, with a mixture of aqueous sodium hydroxide solution and butanol and is subsequently washed with water-and hydrochloric acid.
A hydrolysis of coals is known from the reference "Ind. Engng. Chem. 47 (8), page 1586 (1955)", in which fine coais are fused for 24 hours with a 5n sodium hydroxide
The present invention relates to a method of removing ash components from coals, paxticularly high-ash bituminous and sub-bituminous coals, in which the coals are ground, suspended in aqueous, alkaline-reacting, solutions and the ashes are fused at an elevated temperature and increas-ed pressure under stirring motion and, thereupon, the coals are separated from the a~ueous extract.
A method is known from "BIOS FINAL REPORT 522, item 30", in which the ine coal, freed in advance from a part of its ashes in a ~lotation process, is mixed w~th 5.6 times the amoun~ of a 2.5 percent sodium hydrox-ide ~olution, the suspension i8 kept for 20 minutes under 100 to 200 atm at 250C, the liquor is then separated and the coal is washed with water and hydrochloric acid.
For this purpose, 140 kg of cau~tic soda are needed per metric ton o coal.
~rom U.S. Pa~ent No. 2,556,496, there is further known an ash xemoval process in which the coal is ex-tracted at temperatures bet~en 120C and 130C, with a mixture of aqueous sodium hydroxide solution and butanol and is subsequently washed with water-and hydrochloric acid.
A hydrolysis of coals is known from the reference "Ind. Engng. Chem. 47 (8), page 1586 (1955)", in which fine coais are fused for 24 hours with a 5n sodium hydroxide
2.
~ 0(~69 SOlUtiOll .tt 350C under an increas~d pressure of nitro-gen as a protective gas.
Since ~hese methods for the most part require large amounts o the relatively expensive caustic soda, with no possibility of recovery, they have not prevailed in the industry.
The present invention is directed to a method of remov~ng ash components which can be carried out with a less e~pensive alkali chemical and which in addition makes it possible to regenerate and reuse this chemical in the same process.
In accordance wqth the invention, the gxound coal is suspended in an aqueous alkali carbonate solution and the suspension is kept under agitation or stirring motion for 60 to 120 minutes at 250C to 280C and under a pressure o~ 50 to 80 atm, during which period of time, the C02~ set free by dissociation, is dischaxged by a stream o inert gas. Thereupon, the aqueous ~olution containing the dissolved ash components is separated from the coal and C02 is ~ntroduced into the solution for re-forming alkali carbonate, the content thereby rendered insoluble is sep~rated and, in the alkali carbonate solution, fine coal is again suspended and the ashes are fused.
A potassium or sodium carbonate solution i8 suitable for the i N tial run for the alkali carbonate solution to be used in the process. The a~kali carbonate solution is used in a form which is as concentrated as possible.
At 100C, a trinonmal sodium ~arbonate solution or a hexanormaL potassium carbonate solut~on, for example, is llOOQ69 still sufficiently far from its saturation so as to be able to be handled in the inventive method. The fine coal to be used may be freed from a part of its ash content in advance by a flotation treatment.
The operational conditions applied may vary within large limits and depend on the varying compositions of the coal ashes.
In a preferred variant of the method which is applicable to many varieties of coals, there is used, for example, a trinormal sodium carbonate solution in an amount such that the ash-to-carbonate weight ratio obtained is 2 : 4, and the suspension is treated for 45 to 90 minutes at 250 to 280C and under a pressure of 50 to 80 atm. Nitrogen is particularly suitable as the inert discharge gas.
It i8 advisable to keep the partial pressure of the C02 at 3 to 5 atm. At this pressure, the hydrolysis seems to be part~cularly supported, wh~ch iB manifested by the high pH value of the aqueous phase.
The C02 which is set free at the beginning of the fusion may be collected and used again for the re-formation of the alkali carbonate. It is also possible, however, to employ C02 from foreign sources, such as, for example, in according with a further provision, the C02-containing waste gases of a plant for a direct reduction of ores, particularly iron ores. In this way, a single of a double coupling of technological processes is carried out where, first, the coal is pre-treated and the ash removal is gasified to serve as the
~ 0(~69 SOlUtiOll .tt 350C under an increas~d pressure of nitro-gen as a protective gas.
Since ~hese methods for the most part require large amounts o the relatively expensive caustic soda, with no possibility of recovery, they have not prevailed in the industry.
The present invention is directed to a method of remov~ng ash components which can be carried out with a less e~pensive alkali chemical and which in addition makes it possible to regenerate and reuse this chemical in the same process.
In accordance wqth the invention, the gxound coal is suspended in an aqueous alkali carbonate solution and the suspension is kept under agitation or stirring motion for 60 to 120 minutes at 250C to 280C and under a pressure o~ 50 to 80 atm, during which period of time, the C02~ set free by dissociation, is dischaxged by a stream o inert gas. Thereupon, the aqueous ~olution containing the dissolved ash components is separated from the coal and C02 is ~ntroduced into the solution for re-forming alkali carbonate, the content thereby rendered insoluble is sep~rated and, in the alkali carbonate solution, fine coal is again suspended and the ashes are fused.
A potassium or sodium carbonate solution i8 suitable for the i N tial run for the alkali carbonate solution to be used in the process. The a~kali carbonate solution is used in a form which is as concentrated as possible.
At 100C, a trinonmal sodium ~arbonate solution or a hexanormaL potassium carbonate solut~on, for example, is llOOQ69 still sufficiently far from its saturation so as to be able to be handled in the inventive method. The fine coal to be used may be freed from a part of its ash content in advance by a flotation treatment.
The operational conditions applied may vary within large limits and depend on the varying compositions of the coal ashes.
In a preferred variant of the method which is applicable to many varieties of coals, there is used, for example, a trinormal sodium carbonate solution in an amount such that the ash-to-carbonate weight ratio obtained is 2 : 4, and the suspension is treated for 45 to 90 minutes at 250 to 280C and under a pressure of 50 to 80 atm. Nitrogen is particularly suitable as the inert discharge gas.
It i8 advisable to keep the partial pressure of the C02 at 3 to 5 atm. At this pressure, the hydrolysis seems to be part~cularly supported, wh~ch iB manifested by the high pH value of the aqueous phase.
The C02 which is set free at the beginning of the fusion may be collected and used again for the re-formation of the alkali carbonate. It is also possible, however, to employ C02 from foreign sources, such as, for example, in according with a further provision, the C02-containing waste gases of a plant for a direct reduction of ores, particularly iron ores. In this way, a single of a double coupling of technological processes is carried out where, first, the coal is pre-treated and the ash removal is gasified to serve as the
3~ reduction gas for the ore and, second, the waste gas of the $10CK1 ~9 ore reducing process is used as the CO2 source for regenerating the solution in the coal ash removing process.
The regeneration of the alkali carbonate solution is again advantageously carried out under pressure.
Pressures of between from 50 and 80 atm have proven satisfactory and purposeful in this respect. The method is suitable primarily for bituminous coals and also for older sub-bituminous coals.
With the inventive method, it is possible to reduce the ash content, for example, of 40% to 12%.
Accordingly, it is an object of the invention to provide an improved method of removing ash components from coal in which the coal is ground into ground parti-cles and suspended in an aqueous carbonate solution and wherein the solution is maintained in a reactor for 45 to 120 minutes at a temperature range of from 250C to 280C under a pressure of from 50 to 80 atm in order to cause the CO2 to be set free by dissociation and which is subsequently discharged from the reactor and in which the solution is then stirred and agitated at elevated temperatures and pressures in order to fuse the ashes and then separating the aqueous solut~on containing the dissolved ash components from the coal and further, introducing the removed CO2 into a solution for re-forming an alkali carbonate solution which is used or a further ground coal suspension.
A further object of the invention is to provide a method of removing ash components from high-ash content coals which is easy to carry out, relatively inexpensive and which provides high yields and handles materials economically.
11~6g For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.
The only Figure of the drawing is a diagrammatic view of the apparatus for carrying out the method of the invention.
Referring to the drawing in particular, the invention i5 carried out by using a raw coal which has an ash content of 40% and the ashes contain, as expressed in oxides, the following:
30~ of Al203 45% of SiO2 15% of Fe203 3% of CaO
The regeneration of the alkali carbonate solution is again advantageously carried out under pressure.
Pressures of between from 50 and 80 atm have proven satisfactory and purposeful in this respect. The method is suitable primarily for bituminous coals and also for older sub-bituminous coals.
With the inventive method, it is possible to reduce the ash content, for example, of 40% to 12%.
Accordingly, it is an object of the invention to provide an improved method of removing ash components from coal in which the coal is ground into ground parti-cles and suspended in an aqueous carbonate solution and wherein the solution is maintained in a reactor for 45 to 120 minutes at a temperature range of from 250C to 280C under a pressure of from 50 to 80 atm in order to cause the CO2 to be set free by dissociation and which is subsequently discharged from the reactor and in which the solution is then stirred and agitated at elevated temperatures and pressures in order to fuse the ashes and then separating the aqueous solut~on containing the dissolved ash components from the coal and further, introducing the removed CO2 into a solution for re-forming an alkali carbonate solution which is used or a further ground coal suspension.
A further object of the invention is to provide a method of removing ash components from high-ash content coals which is easy to carry out, relatively inexpensive and which provides high yields and handles materials economically.
11~6g For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.
The only Figure of the drawing is a diagrammatic view of the apparatus for carrying out the method of the invention.
Referring to the drawing in particular, the invention i5 carried out by using a raw coal which has an ash content of 40% and the ashes contain, as expressed in oxides, the following:
30~ of Al203 45% of SiO2 15% of Fe203 3% of CaO
4% of K20 4% of Na20 The raw coal is stored in a bunker 1 and delivered, by a conveying means 2, to a crushing and grading plant 3 where it is ground to such a degree of fineness that 40 to 50% of the grains have a diameter smaller than 44 microns. This fine coal suspension is supplied, through a line 4, to an ash-removing reactor 5 in which it is stirred with a double amount of a 3n soda solution fed in through a line 7, and heated, under a pressure of 60 bar, up to 280C. Nitrogen is introduced into the coal-liquor suspension through a line 6. A mixture of nitrogen and carbon dioxide is removed and discharged into the free atmosphere through a line 8 outgoing from above the liquid surface.
Should substantial amounts of hydrogen sulfide be contained `~' 110QC~69 in the waste gas, the gas is first passed through one of the well~know desulfurizing plants.
After a treatment period of 60 minutes, the coal-liquor suspension is cooled down to 90C in a heat exchange cooler 9a and directed, through a line 9, to a filter 10 in which the coal substance, now containing only 20% of the initial ash content, is separated from the aqueous liquor and rewashed with water from a line lOa.
The separated liquor with the dissolved ash com-ponents which are present, for example, silicates, aluminates, ferrates, etc., as well as the washings, are drawn o~f from filter 10 through a line 11 and conveyed to a carbonizing spray tower 12 where they are exposed at 150C and 20 bar to the action of C02-containing gases which are directed through a line 13. During this treat-ment with gas, water is vaporized and the aqueous liquor is thickened. Residual gases containing mainly water vapor and carbon dioxide are drawn off through a line 14 into the free atmosphere.
Now the carbonized liquor contains not only the soluble alkali carbonates, but also insoluble ash compon-ents, such as silica, aluminum and iron carbonates, etc., and is supplied to a decanter 16 through a line lS. The separated insoluble content is drained as ash sludge through a line 17 and the regenerated carbonate liquor is recycled to ash-removal reactor 5 through line 7. Line 18 serves the purpose of supplying carbonate or hydroxide solutions as a compensation for losses in carbonate liquor.
These losses represent about 0.5% of the entire circulated liquor amount~
X '' ~Q~9.
The filtered and washed pure coal is conveyed into a tank 20 through a line 19 where a coal suspension is produced by adding soft water supplied through a line 21.
The necessary stirrers, pumps, and heaters are not shown.
The suspension is directed through a line 22 to an oxygen pressure gasifier 23 of well-known construction. The residual ashes of the pure coal are discharged through a line 24 and non-gasified carbon in the form of coke or soot is recycled through a line 25 into tank 20. The gas of the gasification is drawn off through a line 26 and stripped from C02 and H2S in a scrubber 27. The scrubbed out C02 and H2S-containing gases are directed through a line 27a for further treatment. The cleaned gasification gas passes through a line 28 into a gas mixer 29 of an iron ore gas reduction plant. In gas mixer 29, the fresh gasification gas is mixed with the circulating gas of the ore reduction plant which has been stripped from carbon dioxide and is fed into gas mixer 29 through a line 30. The mixed gas now passes through a line 31 into a preheater 32 and, from there, through a line 33, into a reduction reactor 34 which is supplied with oxide iron ore through a feed line 35. Iron sponge is removed from reduction reactor 34 thr~ugh a line 36 and the gas through the line 37 and passed into a steam-producing cooler 38 and from there through a line 39 into a dust washer 40.
The gas freed from dust is removed from the circuit through a line 41 and a part thereof through a line 42 for heating purposes (for example, for the ash-removing reactor 5, or the preheater 32 of the reduction gas) and for controlling the inert content. The first part of the ~0(X~69 cooled, dust-free, reduction gas, enriched with CO2, passes into a compressor 43. The compressed gas is directed through a line 44 into a C02 scrubber 44 and, with the CO2 stripped, the clean reduction gas passes through a line 30 to the gas mixer 29 where it is mixed with fresh gasification gas and is recycled into the ore reducing reactor 34. The scrubbed CO2- containing gases are drawn off through line 13 and pass to the carbonizing tower 12. The ash-removing system is connected to the reduction system through line 13 and the gasification plant is connected to the reduction plant through lines 28.
Having described what is believed to be the best mode by which the invention may be performed, it will be seen that the invention may be partially defined as follows:
A method of removing ash components from coals, particularly high ash content coals, comprising grinding the coal into ground particles, suspending the ground coal in an aqueous alkali carbonate solution, maintaining the solution in a reactor for from 45 to 120 minutes at temperature range of from 250C to 280C under a pressure of from 50 to 80 atm in order to cause the CO2 to be set free by dissociation, dis-charging the CO2 by directing an inert gas stream through the reactor and discharging the stream plus the CO2 from the reactor, stirring and agitating the suspension at elevated temperatures and at increased pressures in order to fuse the ashes, separating the aqueous solution with the dissolved ash components from the coal, introducing the removed CO2 into a solution for reforming the alkali carbonate to cause the contents of the so'lution to become insoluble and sepa~tedand causing the alkali solution to become regenerated, using the regenerated alkali solution once again as an aqueous alkali carbonate solution for suspending ground coal The invention further comprises the method having the foregoing features including sodium carbonate solution used for dissolving the high ash components.
Also a three N sodium carbonate solution is preferable for dissolving the ash components. Two to four kilograms of sodium carbonate per kilogram of ashes are preferably used. It is possible, however, to use a six N potassium carbonate solution for dissolving the ash components.
It is advantageous that prior to suspending the coal it is ground and then suspended in a liquid to remove the ash contents by a flotation process. Nitrogen is advantageously used as an inert gas for removing the C02. For dissolving the ash components a C02 partial pressure of from 3 to 5 atmospheres is adjusted.
The C02 set free by dissociation of the alkali carbonates is added in the regeneration of t~e alkali carbonate solution. C02 from foreign processes may be used in the regeneration of the alkali carbonate solution in addition. C02 containing gases separated from the reduc-tion gas circuit in an iron reducing procesR are used in the regeneration of the alkali carbonate solution.
Wh~le a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the ~nvention, it will be understood that the invention may be embodied other-wise without departing from such principles.
10 .
Should substantial amounts of hydrogen sulfide be contained `~' 110QC~69 in the waste gas, the gas is first passed through one of the well~know desulfurizing plants.
After a treatment period of 60 minutes, the coal-liquor suspension is cooled down to 90C in a heat exchange cooler 9a and directed, through a line 9, to a filter 10 in which the coal substance, now containing only 20% of the initial ash content, is separated from the aqueous liquor and rewashed with water from a line lOa.
The separated liquor with the dissolved ash com-ponents which are present, for example, silicates, aluminates, ferrates, etc., as well as the washings, are drawn o~f from filter 10 through a line 11 and conveyed to a carbonizing spray tower 12 where they are exposed at 150C and 20 bar to the action of C02-containing gases which are directed through a line 13. During this treat-ment with gas, water is vaporized and the aqueous liquor is thickened. Residual gases containing mainly water vapor and carbon dioxide are drawn off through a line 14 into the free atmosphere.
Now the carbonized liquor contains not only the soluble alkali carbonates, but also insoluble ash compon-ents, such as silica, aluminum and iron carbonates, etc., and is supplied to a decanter 16 through a line lS. The separated insoluble content is drained as ash sludge through a line 17 and the regenerated carbonate liquor is recycled to ash-removal reactor 5 through line 7. Line 18 serves the purpose of supplying carbonate or hydroxide solutions as a compensation for losses in carbonate liquor.
These losses represent about 0.5% of the entire circulated liquor amount~
X '' ~Q~9.
The filtered and washed pure coal is conveyed into a tank 20 through a line 19 where a coal suspension is produced by adding soft water supplied through a line 21.
The necessary stirrers, pumps, and heaters are not shown.
The suspension is directed through a line 22 to an oxygen pressure gasifier 23 of well-known construction. The residual ashes of the pure coal are discharged through a line 24 and non-gasified carbon in the form of coke or soot is recycled through a line 25 into tank 20. The gas of the gasification is drawn off through a line 26 and stripped from C02 and H2S in a scrubber 27. The scrubbed out C02 and H2S-containing gases are directed through a line 27a for further treatment. The cleaned gasification gas passes through a line 28 into a gas mixer 29 of an iron ore gas reduction plant. In gas mixer 29, the fresh gasification gas is mixed with the circulating gas of the ore reduction plant which has been stripped from carbon dioxide and is fed into gas mixer 29 through a line 30. The mixed gas now passes through a line 31 into a preheater 32 and, from there, through a line 33, into a reduction reactor 34 which is supplied with oxide iron ore through a feed line 35. Iron sponge is removed from reduction reactor 34 thr~ugh a line 36 and the gas through the line 37 and passed into a steam-producing cooler 38 and from there through a line 39 into a dust washer 40.
The gas freed from dust is removed from the circuit through a line 41 and a part thereof through a line 42 for heating purposes (for example, for the ash-removing reactor 5, or the preheater 32 of the reduction gas) and for controlling the inert content. The first part of the ~0(X~69 cooled, dust-free, reduction gas, enriched with CO2, passes into a compressor 43. The compressed gas is directed through a line 44 into a C02 scrubber 44 and, with the CO2 stripped, the clean reduction gas passes through a line 30 to the gas mixer 29 where it is mixed with fresh gasification gas and is recycled into the ore reducing reactor 34. The scrubbed CO2- containing gases are drawn off through line 13 and pass to the carbonizing tower 12. The ash-removing system is connected to the reduction system through line 13 and the gasification plant is connected to the reduction plant through lines 28.
Having described what is believed to be the best mode by which the invention may be performed, it will be seen that the invention may be partially defined as follows:
A method of removing ash components from coals, particularly high ash content coals, comprising grinding the coal into ground particles, suspending the ground coal in an aqueous alkali carbonate solution, maintaining the solution in a reactor for from 45 to 120 minutes at temperature range of from 250C to 280C under a pressure of from 50 to 80 atm in order to cause the CO2 to be set free by dissociation, dis-charging the CO2 by directing an inert gas stream through the reactor and discharging the stream plus the CO2 from the reactor, stirring and agitating the suspension at elevated temperatures and at increased pressures in order to fuse the ashes, separating the aqueous solution with the dissolved ash components from the coal, introducing the removed CO2 into a solution for reforming the alkali carbonate to cause the contents of the so'lution to become insoluble and sepa~tedand causing the alkali solution to become regenerated, using the regenerated alkali solution once again as an aqueous alkali carbonate solution for suspending ground coal The invention further comprises the method having the foregoing features including sodium carbonate solution used for dissolving the high ash components.
Also a three N sodium carbonate solution is preferable for dissolving the ash components. Two to four kilograms of sodium carbonate per kilogram of ashes are preferably used. It is possible, however, to use a six N potassium carbonate solution for dissolving the ash components.
It is advantageous that prior to suspending the coal it is ground and then suspended in a liquid to remove the ash contents by a flotation process. Nitrogen is advantageously used as an inert gas for removing the C02. For dissolving the ash components a C02 partial pressure of from 3 to 5 atmospheres is adjusted.
The C02 set free by dissociation of the alkali carbonates is added in the regeneration of t~e alkali carbonate solution. C02 from foreign processes may be used in the regeneration of the alkali carbonate solution in addition. C02 containing gases separated from the reduc-tion gas circuit in an iron reducing procesR are used in the regeneration of the alkali carbonate solution.
Wh~le a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the ~nvention, it will be understood that the invention may be embodied other-wise without departing from such principles.
10 .
Claims (11)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of removing ash components from coals, particularly high-ash content coals, comprising grinding the coal into ground particles, suspending the ground coal in an aqueous alkali carbonate solution, maintaining the solution under agitation or stirring in a reactor for from 45 to 120 minutes at a temperature range of from 250°C to 280°C under a pressure of from 5 to 80 atm in order to cause the CO2 to be set free by dissocia-tion, discharging the CO2 by directing an inert gas stream through the reactor and discharging the stream plus the CO2 from the reactor, stirring and agitating the suspension at elevated temperatures and at increased pressures in order to fuse the ashes, separating the aqueous solution with the dissolved ash components from the coal, introducing the removed CO2 into a solution for reforming the alkali carbonate to cause the contents of the solution to become insoluble and separated and causing the alkali solution to become regenerated, using the re-generated alkali solution once again as an aqueous alkali carbonate solution for suspending ground coal.
2. A method of removing ash components from coals, according to claim 1, wherein sodium carbonate solution is used for dissolving the ash components.
3. A method of removing ash components from coals, according to claim 1, wherein a 3N sodium carbonate solution is used for dissolving the ash components.
4. A method of removing ash components from coals, according to claim 1, wherein 2 to 4 kg of Na2CO3 per kg of ashes are used.
5. A method of removing ash components from coals, according to claim 1, wherein a 6N potassium carbonate solution is used for dissolving the ash components.
6. A method of removing ash components from coals, according to claim 1, wherein prior to suspending the coal, it is ground and then suspended in a liquid to remove the ash contents by a flotation process.
7, A method of removing ash components from coals, according to claim 1, wherein nitrogen is used as an inert gas for removing the CO2.
8. A method of removing ash components from coals, according to claim 1, wherein for dissolving the ash components, a CO2 partial pressure of from 3 to 5 atm is adjusted.
9. A method of removing ash components from coals, according to claim 1, wherein the CO2 set free by dissociation of the alkali carbonates is added in the regeneration of the alkali carbonate solution.
10. A method of removing ash components from coals, according to claim 1, wherein CO2 from foreign processes is used in the regeneration of the alkali carbonate solution.
11. A method of removing ash components from coals, according to claim 1, wherein CO2-containing gases separated from the reduction gas circuit in an iron reducing process are used in the regeneration of the alkali carbonate solution.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2611619.8 | 1976-03-19 | ||
| DE2611619A DE2611619C2 (en) | 1976-03-19 | 1976-03-19 | Process for the removal of ash components from ash-rich coals |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1100069A true CA1100069A (en) | 1981-04-28 |
Family
ID=5972885
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA274,208A Expired CA1100069A (en) | 1976-03-19 | 1977-03-17 | Method of removing ash components from high-ash content coals |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4099929A (en) |
| JP (1) | JPS52138089A (en) |
| AU (1) | AU2335277A (en) |
| BR (1) | BR7701530A (en) |
| CA (1) | CA1100069A (en) |
| DE (1) | DE2611619C2 (en) |
| ZA (1) | ZA771609B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4329156A (en) * | 1978-08-02 | 1982-05-11 | Othmer Donald F | Desulfurization of coal |
| US4234319A (en) * | 1979-04-25 | 1980-11-18 | The United States Of America As Represented By The United States Department Of Energy | Process for changing caking coals to noncaking coals |
| US4238922A (en) * | 1979-05-11 | 1980-12-16 | Sterling Drug Inc. | Process for the production of power from crude fuels containing high concentrations of sulfur |
| US4282449A (en) * | 1979-08-03 | 1981-08-04 | Combustion Engineering, Inc. | Coal gasifier supplying MHD-steam power plant |
| US4288231A (en) * | 1979-11-13 | 1981-09-08 | Microfuels, Inc. | Coal treatment process |
| JPS57170999A (en) * | 1981-04-15 | 1982-10-21 | Hitachi Zosen Corp | Device for chemical removal of ash from coal |
| US4384536A (en) * | 1981-03-31 | 1983-05-24 | Foster Wheeler Energy Corporation | Desulfurization and improvement of combustion and gasification characteristics of coals |
| US5312462A (en) * | 1991-08-22 | 1994-05-17 | The United States Of America As Represented By The United States Department Of Energy | Moist caustic leaching of coal |
| US8852303B2 (en) * | 2009-12-21 | 2014-10-07 | Southern Company Services, Inc. | High pressure feeder and method of operating to feed granular or fine materials |
| US20120055850A1 (en) * | 2010-09-02 | 2012-03-08 | Emc Metals Corporation | Low carbon dioxide footprint process for coal liquefaction |
| CN106669957B (en) * | 2016-06-20 | 2018-12-28 | 中国矿业大学 | The floatation process of coal in a kind of particulate |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2808369A (en) * | 1952-11-06 | 1957-10-01 | Great Lakes Carbon Corp | Coal purification |
| US3472622A (en) * | 1966-09-19 | 1969-10-14 | Tidewater Oil Co | Desulfurization of coke |
| GB1331524A (en) * | 1971-08-04 | 1973-09-26 | Continental Oil Co | Desulphurising coke |
| US3993455A (en) * | 1973-06-25 | 1976-11-23 | The United States Of America As Represented By The Secretary Of The Interior | Removal of mineral matter including pyrite from coal |
-
1976
- 1976-03-19 DE DE2611619A patent/DE2611619C2/en not_active Expired
-
1977
- 1977-03-11 US US05/776,870 patent/US4099929A/en not_active Expired - Lifetime
- 1977-03-14 BR BR7701530A patent/BR7701530A/en unknown
- 1977-03-17 CA CA274,208A patent/CA1100069A/en not_active Expired
- 1977-03-17 AU AU23352/77A patent/AU2335277A/en active Pending
- 1977-03-17 ZA ZA00771609A patent/ZA771609B/en unknown
- 1977-03-18 JP JP3021077A patent/JPS52138089A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5440561B2 (en) | 1979-12-04 |
| ZA771609B (en) | 1978-01-25 |
| JPS52138089A (en) | 1977-11-17 |
| US4099929A (en) | 1978-07-11 |
| DE2611619C2 (en) | 1982-11-04 |
| DE2611619A1 (en) | 1977-09-22 |
| AU2335277A (en) | 1979-06-21 |
| BR7701530A (en) | 1978-01-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4459138A (en) | Recovery of alkali metal constituents from catalytic coal conversion residues | |
| CA1125208A (en) | Alkali metal recovery process | |
| US3998604A (en) | Demineralization of brown coal | |
| EP0113469B1 (en) | A method for removal of sour water from coal gasification slag | |
| CN1708574B (en) | Process for demineralising coal | |
| CA1100069A (en) | Method of removing ash components from high-ash content coals | |
| US4283379A (en) | Method for removing hydrogen sulfide from gas streams | |
| US4163043A (en) | Process for removing H2 S and CO2 from gases and regenerating the adsorbing solution | |
| CN112125319B (en) | Process for recovering all components of desulfurization waste liquid | |
| US5470361A (en) | Process for working up municipal plastic waste materials by gasification | |
| GB2056425A (en) | Treatment of wastes containing water-leachable fluorides | |
| US5085764A (en) | Process for upgrading coal | |
| US4420464A (en) | Recovery of vanadium from carbonaceous materials | |
| EP0016624B1 (en) | Coal de-ashing process | |
| JPS6039116B2 (en) | Method for recovering alkali metal compounds for reuse in a catalytic coal conversion process | |
| US5112586A (en) | Process for purification of synthesis gas | |
| US5059307A (en) | Process for upgrading coal | |
| CA1106788A (en) | Coal desulfurization using silicates | |
| US4098583A (en) | Method of removing ash components from high-ash coals | |
| JPS63191894A (en) | Treatment of fly slag | |
| US4174953A (en) | Process for removing sulfur from coal | |
| CN109110859A (en) | A kind of coking desulfurization waste liquor advanced treatment process | |
| JPS6035092A (en) | Collection of alkali metal catalyst components from coal conversion residue | |
| US4008145A (en) | Converting solid fuels to gaseous and liquid fuels | |
| EP0099429B1 (en) | The recovery of alkali metal constituents from catalytic coal conversion residues |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |